My oil burner works fine while firing, but when it shuts off, there is fuel oil continuing to come from the nozzle. I get flames outside the combustion chamber when this happens, and I can find no information related to some kind of "check valve" to stop this flow...can anyone help? The unit is a Beckett and it is around 15 years old. It's a model "A" "AF" series burner with a A2VA-7116 fuel pump.

I guess maybe the programmer/timer or other circuitry is defective and preventing power being supplied to the spark generator and/or fuel pump/combustion fan or perhaps the flame monitoring circuitry isn't working.

When a light oil burner starts the ignition spark is switched on first followed by the combustion fan and then the fuel pump supplies fuel to the spray nozzle under pressure and produces a jet of fine mist which ignites. If the flame dies the flame monitor signal also dies and the safety circuitry shuts off the pump.

That is roughly how many light oil burners work and as you now know there is a lot that should be happening, that is unlikely to happen if everything isn't in good order due to the requirement for safety.

Some Rg3 information is available to download if you are interested but if you want your boiler working quickly I advise you contact a professional.

guessing the thermacouple may be failing as this part tells the fuel metering system if the burner is hot enough to maintain safe combustion

It sounds as though the control may not be the problem. Is the burner actually firing ? Are you getting a good strong flame?. If so the cad cell may be the problem . Make sure the wiring to the cad cell is correct and there is nothing blocking the cell from the flame.
Try a different cad cell to see if that solves the problem. If you are not getting flame check the transformer. If that is okay check the gap of the electrodes. Hope this helps

Commonly Reported HVAC Problems: [Copyright © 1996-2011. Hannabery HVAC. All rights reserved.]That would be the little red button on the box at the oil burner itself. If your oil burner stops running the first thing you should check is the reset button. If you press it and the burner fires up then that was the problem. If the button should trip again then there is a definite problem and you should schedule a service call immediately. Do not keep resetting the button and ignoring the problem. Now, what is this button and why does it trip? It is a safety device. It shuts the burner down when it thinks there is a problem. It is on the primary control and is hooked-up to a cad cell. A light sensor. (The same thing that turns outside lights on at dusk.)
On a call for heat, with the burner running, the cad cell senses the light of the flame. If it stops sensing the light of the flame, it causes the red button to trip, shutting down the burner before any significant damage is done. Next question. Why would the sensor stop sensing light while the burner is running? Many reasons. Almost all of which require a service call. Below is a list of possible causes and things to check. Items in blue usually require a service call. Items in red however can be addressed, even fixed by the homeowner.

• Faulty or dirty cad cell
• Faulty primary control
• Bad or weak ignition transformer
• Bad burner motor
• Bad fuel pump
• Blocked oil filter, strainer or nozzle
• Delayed oil valve not opening (some units)
• Cracked electrodes
• Improperly set electrodes
• Air in fuel line
• Burner running with a very high smoke
• Burner sooted-up
• Loose electrical connections
• Damaged flexible coupling
• Water in oil tank

• Out of oil - Have your tank filled
• Chimney blocked - Have it cleaned
• Closed oil valve - Open valve
• Air, Pump not primed - Prime pump - may need to call for service

Oil filter refills
Oil filter canister
Smart Filters
The bottom causes in red are common problems and can be addressed by the homeowner. Try to check for these conditions first before calling for service. Hope this helps, remember - these are just rough guidelines and not all possible situations are covered.

I found this article on the Web So I can't take credit for it..... But it is a very good place to start for your problem It is what I would start checking if you called me for service .......Good Luck

If it always shuts down during the night it could be an air adjustment, during the nighttime the humidity and temperature both drop making the air denser with oxygen and "can" cause the initial light off to be so lean that the flame does not fully ignite. If there is an air adjustment move it (slightly) to a smaller number reducing the amount of combustion air which richens the mixture of oxygen and hydrocarbons (fuel). A rich mix will light reliably, too rich and you will make soot during burner operation so if the trick works more is not better, don't soot up your furnace or vent pipe by going too far.

This can be a result of several things. The most common problem is the photo sensor. If there is a flame, and the photo sensor can't detect it - the furnace will shut down. If the furnace has run dirty and sooty - there's probably black soot covering the sensor, blocking the light of the flame. Remove, wipe the lens, and reassemble. Try for ignition again. Keep in mind, after three unsuccessful starts, the primary control will shut down in lock out mode. This is to prevent an additional start as the chamber is probably soaked with heating oil. It should be cleaned completely before attempting ignition again.

The filter may be sufficiently blocked to prevent fuel to flow at a rate the burner needs. Replacing it may be required. If not a dirty filter, lines may be clogged by bacteria in the oil that has clogged them. You might need to have the lines blown back to the tank with a compressed air tool designed specifically for this purpose. Air in the fuel line can cause the flame to go out, and once out it will not restart without the spark. This can be caused by the constant vibration of the burner. A loose coupling between the blower and oil pump can cause the flame to go out, as could a faulty oil pump. Too little combustion air can cause soot - too much is almost as bad.

The real problem is lack of professional maintenance. An oil burner needs to be tuned, not just cleaned. Proper air / fuel mixtures, nozzles replaced when worn, heat damaged parts replaced, clean heat exchangers, stack temperatures, draft, etc. must all be "tweaked." for optimum performance. A properly tuned traditional burner can be 86% efficient - newer styles well over 90%. But they won't stay that way without annual tuning. With the cost of heating oil, why settle for less than optimum efficiency?

Good luck!

Oil furnaces have certain items that routinely go bad or need adjusted to work properly.Some of the common things are nozzle, then gap and location of the igniter,then last is the fire eye. You can see all of these items by pulling the burner tray out. The nozzle delivers the fuel in two ways more or less, first is spray angle then second is the rate or GPH. Nozzles are to spray an atomized mist this means no heavy droplets of fuel. If you have large drops of oil chances are a new nozzle can help you out, please pay attention to spray angle and GPH. The igniter is next, after time they will wear and you can clean the rods and reset the gap to specified distance, that being said it also needs to be a certain distance from the atomized fuel to ignite properly all very important. Then last is the fire eye it tells the furnace that a flame is established and to deliver fuel or flame out and shuts fuel down. These will build carbon deposits at times so simply clean off the deposit and clean the lens with a soft cloth and windex reposition put the burner tray back in hook up the fuel line and off you go.

There is a flame sensor inside the burner unit. The sensor is like a photo cell that must see the light of the flame or it will tell the burner control to stop the power. You need to see if there is a soot film on the lense of the sensor and make sure the sensor is aimed straight. If the sensor is clean and aimed straight (and the problem persists) then there may be a clogged nozzle that is giving a poor flame and the sensor does not see a good flame therefore shuts down the unit. If the nozzle is at fault, then you for sure need to replace the oil filter. New nozzles are $4-8 and the size & spray angle is stamped on the nozzle. If there is still a problem, then you need to see if the pump is giving approx. 100psi pressure, then finally (the last step) would be to replace the burner control $60. Goodluck< Macgivor

Hey welcome to the world of oil burner service!! :-) Theyare a finnicky beast to say the least. The problem you are having sounds like an air mixture problem. A combustion analyser would be the best tool to have but being that you probably don't have that try this. On the left side of the burner as you are looking at it is an air adjust ment ring and a fine tuning ring. the fine tuning ring is probably all you need to adjust. There is a screw that is usually right behind or near the pipe coming out of the pump and going into the burner. Loosen that and turn the ring away from you just a bit to close off some of the air and you will be fine. The burner is running a bit to lean. If you can see the flame turn the adjustment closed just until the flame color turns from a almost white color to a slightly orange color. Then you should be fine. Good luck!!

open bleed screw being careful not to get it all over the place